1,4,7-Triazacyclononane, known as "TACN" which is pronounced "tack-en," is an aza-crown ether with the formula (C2H4NH)3.[1] TACN is derived, formally speaking, from cyclononane by replacing three equidistant CH2 groups with NH groups. TACN is one of the oligomers derived from aziridine, C2H4NH. Other members of the series include piperazine, C4H8(NH)2, and the cyclic tetramer 1,4,7,10-tetraazacyclododecane.
TACN is a popular tridentate ligand. It is threefold symmetric and binds to one face of an octahedron of metalloids and transition metals. The (TACN)M unit is kinetically inert, allowing further synthetic transformations on the other coordination sites. A bulky analogue of TACN, is the N,N',N"-trimethylated analogue trimethyltriazacyclononane.
Illustrative complexesedit
Although TACN characteristically coordinates to metals in mid- and high oxidation states, e.g. Ni(III), Mn(IV), Mo(III), W(III), exceptions occur. To illustrate, 1,4,7-triazacyclononane reacts readily with Mo(CO)6 and W(CO)6 to produce the respective air-stable tricarbonyl compounds, [(κ3 -TACN)Mo(CO)3] and [(κ3-TACN)W(CO)3]. Both have an oxidation state of zero. After further reacting with 30% H2O2, the products are [(κ3-TACN)MoO3] and [(κ3-TACN)WO3]. Both of these oxo complexes have an oxidation state of 6. The macrocyclic ligand does dissociate in the course of this dramatic change in formal oxidation state of the metal.
The complex, [κ3-TACN)Cu(II)Cl2], a catalyst for hydrolytic cleavage of phosphodiester bonds in DNA,[3] is prepared as follows from TACN trihydrochloride:
Mn-TACN complexes catalyze epoxidation of alkenes such as styrene using H2O2 as an oxidant in a carbonate buffered methanol solution at a pH of 8.0. These reagents are considered environmentally benign,[4]
Chromium (II) sources, e.g. created by heating CrCl3.6H2O in DMSO react with TACN to form both 1:1 Cr:and 2:1 complexes,[5] e.g. yellow [(TACN)2Cr]3+.[6]
Referencesedit
^Chaudhuri, P.; Wieghardt, K. (1987). "The Chemistry of 1,4,7-Triazacyclononane and Related Tridentate Macrocyclic Compounds". In Lippard, Stephen J. (ed.). Progress in Inorganic Chemistry. Vol. 35. Hoboken, NJ, USA: John Wiley & Sons, Inc. pp. 329–436. doi:10.1002/9780470166369.ch4. ISBN9780470166369.
^Wieghardt, Karl; Schmidt, Wilfried; Nuber, Bernhard; Weiss, Johannes (1979). "Darstellung und Struktur des trans-Diaqua-di-μ-hydroxo-bis[(1,4,7-triazacyclononan)cobalt(III)]-Kations; Kinetik und Mechanismus seiner Bildung". Chemische Berichte (in German). 112 (6): 2220–2230. doi:10.1002/cber.19791120629.
^Sibbons, Kevin F.; Shastri, Kirtida; Watkinson, Michael (2006). "The application of manganese complexes of ligands derived from 1,4,7-triazacyclononane in oxidative catalysis". Dalton Transactions (5): 645–661. doi:10.1039/B511331H. PMID 16429167.
^Deal, Kim A.; Burstyn, Judith N. (1996). "Mechanistic Studies of Dichloro(1,4,7-triazacyclononane)copper(II)-Catalyzed Phosphate Diester Hydrolysis". Inorg. Chem. 35 (10): 2792–2798. doi:10.1021/ic951488l.
^Wieghardt, Karl; Schmidt, Wilfried; Endres, Helmut; Wolfe, C. Robert (1979). "Neue μ-Hydroxo-Übergangsmetallkomplexe, II. Darstellung mehrkerniger Komplexe des Chroms(III) mit dreizähnigen Amin-Liganden. Struktur des μ[cis-Dihydroxo(O,O′)-hydroxo(l,4,7-triazacyclononan)chrom(III)]-di-μ-hydroxobis[(1,4,7-triazacyclononan)chrom(III)]-Kations". Chemische Berichte (in German). 112 (8): 2837–2846. doi:10.1002/cber.19791120810.
^Wieghardt, K.; Schmidt, W.; Hermann, W.; Küppers, H.-J. (1983). "Redox potentials of bis(1,4,7-triazacyclononane complexes of some first transition series metals(II,III). Preparation of bis(1,4,7-triazacyclononane)nickel(III) perchlorate". Inorg. Chem. 22 (20): 2953. doi:10.1021/ic00162a037.
December 18, 2023
triazacyclononane, known, tacn, which, pronounced, tack, crown, ether, with, formula, c2h4nh, tacn, derived, formally, speaking, from, cyclononane, replacing, three, equidistant, groups, with, groups, tacn, oligomers, derived, from, aziridine, c2h4nh, other, m. 1 4 7 Triazacyclononane known as TACN which is pronounced tack en is an aza crown ether with the formula C2H4NH 3 1 TACN is derived formally speaking from cyclononane by replacing three equidistant CH2 groups with NH groups TACN is one of the oligomers derived from aziridine C2H4NH Other members of the series include piperazine C4H8 NH 2 and the cyclic tetramer 1 4 7 10 tetraazacyclododecane 1 4 7 Triazacyclononane NamesPreferred IUPAC name 1 4 7 TriazonaneIdentifiersCAS Number 4730 54 5 Y3D model JSmol Interactive imageBeilstein Reference 773877ChEBI CHEBI 37405 YChEMBL ChEMBL1650628ChemSpider 163681 YECHA InfoCard 100 164 887EC Number 637 157 5Gmelin Reference 2614PubChem CID 188318UNII 2UIF93C5H3 YCompTox Dashboard EPA DTXSID50197095InChI InChI 1S C6H15N3 c1 2 8 5 6 9 4 3 7 1 h7 9H 1 6H2 YKey ITWBWJFEJCHKSN UHFFFAOYSA N YInChI 1 C6H15N3 c1 2 8 5 6 9 4 3 7 1 h7 9H 1 6H2Key ITWBWJFEJCHKSN UHFFFAOYASSMILES C1CNCCNCCN1PropertiesChemical formula C6H15N3Molar mass 129 2046 g molHazardsGHS labelling PictogramsSignal word DangerHazard statements H314Precautionary statements P260 P264 P280 P301 P330 P331 P303 P361 P353 P304 P340 P305 P351 P338 P310 P321 P363 P405 P501Except where otherwise noted data are given for materials in their standard state at 25 C 77 F 100 kPa N verify what is Y N Infobox references Contents 1 Synthesis 2 Coordination chemistry 2 1 Illustrative complexes 3 ReferencesSynthesis editThe ligand is prepared from diethylene triamine as follows by macrocyclization using ethyleneglycol ditosylate 2 H2NCH2CH2NHCH2CH2NH2 3 TsCl Ts H NCH2CH2N Ts CH2CHH2N H Ts 3 HCl Ts H NCH2CH2N Ts CH2CH2N H Ts 2 NaOEt Ts Na NCH2CH2N Ts CH2CH2N Na Ts Ts Na NCHH2CH2N Ts CH2CH2N Na Ts TsOCH2CH2OTs CH2CH2N Ts 3 2 NaOTs CH2CH2N Ts 3 3 H2O CH2CH2NH 3 3 HOTsCoordination chemistry editTACN is a popular tridentate ligand It is threefold symmetric and binds to one face of an octahedron of metalloids and transition metals The TACN M unit is kinetically inert allowing further synthetic transformations on the other coordination sites A bulky analogue of TACN is the N N N trimethylated analogue trimethyltriazacyclononane Illustrative complexes edit Although TACN characteristically coordinates to metals in mid and high oxidation states e g Ni III Mn IV Mo III W III exceptions occur To illustrate 1 4 7 triazacyclononane reacts readily with Mo CO 6 and W CO 6 to produce the respective air stable tricarbonyl compounds k3 TACN Mo CO 3 and k3 TACN W CO 3 Both have an oxidation state of zero After further reacting with 30 H2O2 the products are k3 TACN MoO3 and k3 TACN WO3 Both of these oxo complexes have an oxidation state of 6 The macrocyclic ligand does dissociate in the course of this dramatic change in formal oxidation state of the metal The complex k3 TACN Cu II Cl2 a catalyst for hydrolytic cleavage of phosphodiester bonds in DNA 3 is prepared as follows from TACN trihydrochloride TACN 3HCl CuCl2 3H2O 3 NaOH k3 TACN CuCl2 6 H2O 3 NaClMn TACN complexes catalyze epoxidation of alkenes such as styrene using H2O2 as an oxidant in a carbonate buffered methanol solution at a pH of 8 0 These reagents are considered environmentally benign 4 k3 TACN Mn H2O2 NaHCO3 C6H5 C2H3 k3 TACN Mn 2H2O CO2 C6H5 C2H2OChromium II sources e g created by heating CrCl3 6H2O in DMSO react with TACN to form both 1 1 Cr and 2 1 complexes 5 e g yellow TACN 2Cr 3 6 References edit Chaudhuri P Wieghardt K 1987 The Chemistry of 1 4 7 Triazacyclononane and Related Tridentate Macrocyclic Compounds In Lippard Stephen J ed Progress in Inorganic Chemistry Vol 35 Hoboken NJ USA John Wiley amp Sons Inc pp 329 436 doi 10 1002 9780470166369 ch4 ISBN 9780470166369 Wieghardt Karl Schmidt Wilfried Nuber Bernhard Weiss Johannes 1979 Darstellung und Struktur des trans Diaqua di m hydroxo bis 1 4 7 triazacyclononan cobalt III Kations Kinetik und Mechanismus seiner Bildung Chemische Berichte in German 112 6 2220 2230 doi 10 1002 cber 19791120629 Sibbons Kevin F Shastri Kirtida Watkinson Michael 2006 The application of manganese complexes of ligands derived from 1 4 7 triazacyclononane in oxidative catalysis Dalton Transactions 5 645 661 doi 10 1039 B511331H PMID 16429167 Deal Kim A Burstyn Judith N 1996 Mechanistic Studies of Dichloro 1 4 7 triazacyclononane copper II Catalyzed Phosphate Diester Hydrolysis Inorg Chem 35 10 2792 2798 doi 10 1021 ic951488l Wieghardt Karl Schmidt Wilfried Endres Helmut Wolfe C Robert 1979 Neue m Hydroxo Ubergangsmetallkomplexe II Darstellung mehrkerniger Komplexe des Chroms III mit dreizahnigen Amin Liganden Struktur des m cis Dihydroxo O O hydroxo l 4 7 triazacyclononan chrom III di m hydroxobis 1 4 7 triazacyclononan chrom III Kations Chemische Berichte in German 112 8 2837 2846 doi 10 1002 cber 19791120810 Wieghardt K Schmidt W Hermann W Kuppers H J 1983 Redox potentials of bis 1 4 7 triazacyclononane complexes of some first transition series metals II III Preparation of bis 1 4 7 triazacyclononane nickel III perchlorate Inorg Chem 22 20 2953 doi 10 1021 ic00162a037 Retrieved from https en wikipedia org w index php title 1 4 7 Triazacyclononane amp oldid 1093988782, wikipedia, wiki, book, books, library,
